Gaza received 20,000 doses of Russia's Sputnik V vaccine from the United Arab Emirates on Sunday, a move secured by Palestinian President Mahmoud Abbas's rival, Mohammad Dahlan, who is based in the Gulf state.
Gaza health officials said they would begin vaccination on Monday, with priority for medical workers and those with chronic diseases. Many patients were contacted in advance and asked to give their consent.
The step by Dahlan, whom Abbas had dismissed from his Fatah party a decade ago and forced into exile, was seen by analysts as an attempt to score points ahead of a planned Palestinian election later this year.
"The shipment is a generous offer from the brotherly UAE," Dahlan, long considered a potential Abbas successor, said on Facebook. "We promise our people that we will exert every possible effort to secure more."
Gaza received its first 2,000 doses of Sputnik V on Wednesday, sent by Abbas's government after Israel approved the transfer through its border with the territory, which is controlled by the Palestinian leader's Islamist Hamas rivals.
Gaza, an impoverished enclave of two million people, has registered more than 54,000 cases with 543 deaths.
In August, the UAE angered Palestinians when it struck a diplomatic deal with Israel, a move Abbas described as "betrayal". Some criticized Dahlan for failing to condemn the accord, while others suggested he may have played a role.
He has not outright denied this. But his faction has criticised Arab countries forming relations with Israel before its conflict with the Palestinians is resolved.
Dahlan had said his strong ties with the UAE helped him raise hundreds of millions of dollars in aid for Palestinians.
In Gaza and the West Bank, Palestinians gave mixed responses.
"How can you thank the Emirates? (They) gave up on our cause and normalized with the Israelis," said one post.
Another said: "All hail the true leader, Mohammad Dahlan, who cares for his people, supports them in all areas of life and stands for them in all circumstances."
Once a fierce foe of Hamas, Dahlan has in recent years improved his ties with its rulers, permitting his associates to operate more freely in the territory.